C++11/14學習（四）初始化列表

int arr[3] = { 1,2,3 }; // 列表初始化
class Foo
{
private:
    int value;
public:
    Foo(int) {}
};
Foo foo(1); // 普通構造初始化

int static_arr[5] = { 1, 2, 3, 4 };
int static_arr2[]{ 1, 2, 3, 4 }; // 等號要以省略
int* dynamic_arr = new int[5]{ 1, 2, 3, 4 };
vector<int> stl_vec{ 1, 2, 3, 4 };
set<int> stl_set{ 1, 2, 3, 3 };
map<const char*, int> stl_map
{
    { "Alice", 1 },
    { "Bob", 2 },
    { "Cindy", 3 }
};

#include <initializer_list> // This header is required
#include <iostream>

using namespace std;

template <class Tp>
void print_ilist(const initializer_list<Tp> &ilist)
{
    for (auto it = ilist.begin(); it != ilist.end(); ++it)
        cout << *it << endl;
}

struct Foo
{
    int vals[10];
    int n = 0;

    Foo(const initializer_list<int> &ilist) {
        for (int v : ilist)
            vals[n++] = v;
    }
};

int main()
{
    initializer_list<int> empty_ilist;
    empty_ilist = { 1, 2, 3, 4 };
    cout << empty_ilist.size() << endl; // 4

    Foo foo{ 1, 2, 3 };
    Foo bar(empty_ilist);
    cout << "bar.n = " << bar.n << endl; // 4

    initializer_list<float> float_ilist{ 1.0, 1.2, 1.5, 2.0 };
    print_ilist(float_ilist);
    print_ilist({ "Reimu", "Marisa", "Sanae", "Reisen" });
    return 0;
}